Device for recanalization of vessel occlusions using guide wire and method of use

ABSTRACT

An attachment mechanism and method for attaching or coupling a guide wire to a catheter for re-canalization or opening a passage through an occlusion in a blood vessel is provided. The attachment mechanism generates friction forces against the guide wire to couple the guide wire to a catheter, which design permits a greater force to be used on the guide wire during a re-canalization procedure. The invention also encompasses use of the attachment mechanism in conjunction with active catheters, which have vibration-generating means to oscillate the distal end of the catheter or a component in the distal end of the catheter, to add vibration motion, preferably axial vibration motion, to the increased force that may be applied to the guide wire for purposes of penetrating an occlusion. The methods of the invention relate to methods of attaching the guide wire to the catheter and methods of treating a vessel having a partial or total occlusion.

This application is a divisional of U.S. patent application Ser. No.13/022,731, filed Feb. 8, 2011, and claims the benefit of priority ofU.S. Provisional Application Ser. No. 61/302,679, filed Feb. 9, 2010,both of which are incorporated herein by reference in their entireties.

FIELD OF THE INVENTION

The invention is directed to the use of a guide wire within a supportcatheter or active catheter for penetrating a total occlusion of a bloodvessel during percutaneous coronary intervention (“PCI”) using a guidewire. In particular, the apparatus provides a mechanism for enhancingthe axial force that may be applied to the guide wire, or fortransferring vibration energy to a guide wire at the distal tip of thePCI device, to use the distal end of the guide wire to penetrate theocclusion.

BACKGROUND OF THE INVENTION

Medical science has long sought effective treatments for diseaseconditions involving stenosis (narrowing or obstruction) of the lumen ofan artery. This condition, known generally as an occlusion, occurs inpatients suffering from atherosclerosis, which is characterized by anaccumulation of fibrous, fatty or calcified tissue in the arteries,otherwise known as atheromata or plaques. An occlusion may be partial ortotal; it may be soft and pliable or hard and calcified. Occlusions canarise at a great variety of sites in the arterial system including theaorta, the coronary and carotid arteries, and peripheral arteries. Anocclusion can result in hypertension, ischemia, angina, myocardialinfarction, stroke and even death.

Minimally invasive procedures are the preferred treatment of arterialocclusions. In these procedures, a catheter—a long, highly flexibletubular device—is introduced into a major artery through a smallarterial puncture made in the groin, upper arm, upper leg, or neck. Thecatheter is advanced and steered into the site of the stenosis. A greatvariety of devices have been developed for treating the stenosed artery,and these devices are placed at the distal end of the catheter anddelivered thereby. Example procedures include percutaneous transluminalcoronary angioplasty (PTCA), directional coronary atherectomy (DCA), andstenting.

In a total occlusion, a passageway must first be opened through theocclusion to allow the balloon/stent catheter to be placed in the targetstenosed segment of the vessel. As occlusion morphology is complicatedand varies from patient to patient, common methods and devices foropening these occlusions have had limited success and require longprocedures with potentially adverse effects on the patient. Such adverseeffects include perforation of blood vessel wall, high radiation dose ordamage to kidneys due to extensive use of angiographic contrastmaterial.

Stenoses, or occlusions, are made of a variety of materials—from softerfatty substances such as cholesterol, to tougher fibrous material, tohard calcified material. Generally the ends of the occlusion—theproximal and distal caps—comprise the harder calcified material. Theharder materials are more difficult to penetrate, requiring asignificant amount of energy, the softer materials require less energy.Therefore, opening an occlusion requires transfer of relativelyextensive energy to the distal end of a catheter or guide wire,especially when calcification is present.

Some available methods for opening total occlusions are radio-frequencyablative energy (as used in the system sold by Intralumenal Therapeuticsas Safecross™), vibrational energy of about 20 kHz and small amplitudes(as used in the system sold by FlowCardia Inc. as Crosser™), dedicatedstiff guide wire which pushes a passage through the occlusion (asdeveloped by Asahi Intec Co. and distributed as Confianza 9g/Conquestand Miracle 12g guide wires) and mechanical vibration elements workingat high frequency (FlowCardia Inc.'s Crosser™). The latter means foropening occlusions suffer from significant energy loss between theenergy source at the proximal end of the catheter and the drillerlocated at the distal end of the catheter, as well as limited workinglife due to material fatigue. For example, with an ultrasound catheter,the ultrasonic energy usually originates from an ultrasound transducerat the proximal end of the catheter and is then transmitted to thedistal head of the catheter as a sinusoidal wave, causing the distalhead to vibrate and either ablate or disrupt the target occlusion.

To reach treatment sites, such catheters must be rather long—about90-150 cm or more—and therefore a large amount of energy must initiallybe transmitted to reach the distal end. At the same time, to be flexibleenough to course through highly tortuous vessels, the catheter must bereasonably thin. The long length and narrow diameter combine to makewire breakage a common problem due to the stress and wear from the highenergy pulses. Guide wires stiff enough to penetrate hard occlusionshave the disadvantage that their inflexibility and straight tips makenavigating through tortuous vessels difficult and increase the risk ofvessel perforation. Rigid materials that are sufficiently flexible toaccommodate the highly tortuous vessels have the problem of buckling,due to the proximal location of the pushing source. Buckling results inenergy loss by transfer to transverse forces and friction against thelumen housing the rigid material. All such devices provide limitedsuccess rate ranging from 40-70%.

Occlusions comprise a variety of materials of different density andhardness. Therefore, the nature of the energy used in a re-canalizationdevice should suit the specific occlusion and the penetration should becontrolled to prevent perforation of the artery walls or damage tohealthy tissue. Additionally, because the energy originates at theproximal end of the catheter it must be able to reach the distal end ofthe device near the occlusion at a level sufficient to effectpenetration of the occlusion without damaging the conductive wires andwithout sacrificing flexibility of the device. As previously described,current devices suffer either from an insufficient amount of energytransferred to the distal end of the device or a mismatch between thetype of energy delivered and the type of occlusion, sometimes resultingin too much force being applied and thereby increasing the risk ofdamage, or even perforation, of the lumen wall. Accordingly, there is aneed for a system or apparatus that can transfer adequate energy to there-canalization device.

Guide wires are used for navigation within blood vessels, guidingvarious catheters through blood vessels, and for specific applicationssuch as re-canalization of partial or full occlusions of blood vessels.The guide wires widely used in interventional cardiology and radiology(peripheral and cardiovascular) generally have a variety of diameters(e.g., 0.014 inches, 0.018 inches, 0.035 inches). These small diameterslimit the force that may be applied and transferred to the tip of theguide wire for such purposes (typically several grams to about 15 gramsfor stiff wires) and also limit the control available for activelydirecting the guide wire through obstacles, for example to cross avessel occlusion.

Therefore, there is a need for an apparatus for penetrating vesselocclusions comprising a guide wire that allows a greater force to beapplied at the distal end of a guide wire for penetrating a partial orfull occlusion, as well as a device that assists traversing obstacles ortortuous elements within blood vessels with a guide wire. There also isa need in the art for an apparatus for penetrating vessel occlusionscomprising a guide wire that avoids the problem of energy transfer fromthe proximal to distal end of the catheter and that improves theusefulness of a stiff guide wire as the structure for penetrating avessel occlusion.

SUMMARY OF THE INVENTION

It is an object of the invention to provide an apparatus for penetratinga vessel occlusion that is able to reversibly attach or couple a guidewire to catheter to enhance the force that may be applied to penetrate avessel occlusion using the distal tip of the guide wire. It is a furtherobject of the invention to couple a guide wire to a catheter usingfriction forces applied to the guide wire to enhance control of theguide wire for penetrating a vessel occlusion.

The present invention is directed to an apparatus for penetrating avessel occlusion, where the apparatus has a guide wire and a mechanismfor attaching or coupling the guide wire to the catheter, preferably thedistal end of the catheter and preferably during distal vibration. Theguide wire is attached to the catheter by friction forces between theguide wire and a guide wire attachment lumen generated in broad terms bymovement of the catheter and in specific terms by the particularembodiment of the attachment mechanism that utilizes this principle. Thecatheter may be a passive catheter or an active catheter. By “passivecatheter” is meant a standard endovascular catheter that may be used forcurrent stiff wire re-canalization procedures. By “active catheter” ismeant a catheter that has a mechanism for generating a vibration at thedistal end of the catheter for penetrating an occlusion. Coupling theguide wire to the passive catheter in accordance with the inventionpermits use of the catheter, which inherently has better push-abilitythan the guide wire, to push or pull the distal end of the guide wire,to significantly enhance the axial force that may be applied to theguide wire to penetrate a vessel occlusion. Moreover, when theattachment mechanism of the invention is used with an active catheter,the vibrational motion generated in the catheter may be transferred tothe guide wire in conjunction with the increased axial force, to furtherenhance the occlusion penetrating capabilities of the guide wire. Theattachment lumen may be a portion of the guide lumen or it may be aspecially designed lumen through which the guide wire passes.

The guide wire attachment mechanism of the invention attaches the guidewire to the catheter based on movement of the portion of the catheterwhere the attachment mechanism is located, for example by accelerationforce, by a particular direction of movement of the portion of thecatheter, or by movement of a specially designed lumen through which theguide wire passes. The motion or acceleration generates frictionalforces against the guide wire by the wall of the attachment lumensurrounding the guide wire that couples the guide wire to the catheter.The frictional forces are created by the guide wire being pressed upagainst the wall of an attachment lumen by a piston, or by the guidewire being bent relative to the attachment lumen. As the coupling isforce-limited and the force is reduced in the absence of a vibrationforce or in the absence of movement of the catheter cap, the operatorcan used the guide wire in a standard manner as well.

An advantage of the present invention is that by attaching the guidewire to the catheter in a reversible—that is force-specific—manner, andin particular when attachment of the guide wire is at the distal end ofthe catheter, the force that may be applied against the occlusion usinga guide wire may be greater than that possible using a stiff guide wireand a standard catheter without the attachment mechanism. Further,control over the guide wire tip during occlusion penetration isimproved, because the guide wire may be locked in the catheter. Stillfurther, when used in conjunction with an apparatus that generates avibration in the distal tip of the catheter, the attachment mechanism ofthe invention permits transfer of the vibration motion to the guide wirein addition to the increased force that may be applied to the guide wireto penetrate the occlusion.

DESCRIPTION OF DRAWINGS

FIGS. 1A-B illustrate the operation of an embodiment of the apparatus ofinvention comprising acceleration pistons. FIG. 1A depicts in a cut-awayview the locking of a guide wire upon forward acceleration, and FIG. 1Bdepicts in a cut-away view the locking of a guide wire upon backwardacceleration.

FIG. 2 illustrates in cross-section an embodiment of the apparatus ofthe invention in which a spring piston may be positioned to favorattachment of the guide wire based on movement of the guide wire in onedirection over another.

FIG. 3 illustrates in cross-section an embodiment of the guide wireattachment mechanism in which a attachment lumen has a curve so as tobend the guide wire and create sufficient friction at certain forces toeffectively attach the guide wire to the catheter.

FIG. 4 illustrates in cross-section the embodiment of FIG. 3 used inconjunction with an active catheter comprising a vibration-generatingmeans.

FIGS. 5A and 5B illustrate in cross-section embodiments of the guidewire attachment mechanism in which the attachment lumen has a frictionalsurface that includes a high friction flexible polymer. FIG. 5A depictsan embodiment in which the attachment lumen is parallel to thelongitudinal axis of the catheter cap; FIG. 5B depicts an embodiment inwhich the attachment lumen is set at an angle relative to thelongitudinal axis of the catheter cap.

FIGS. 6A and 6B illustrate in cross-section an embodiment of the guidewire attachment mechanism in which the attachment lumen has a frictionalsurface that includes a flexible tube. FIG. 6A depicts an embodiment inwhich the attachment lumen is parallel to the longitudinal axis of thecatheter cap; FIG. 6B depicts an embodiment in which the attachmentlumen is set at an angle relative to the longitudinal axis of thecatheter cap.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides an apparatus and method for improvedguide wire-based re-canalization of a partial or total occlusion in ablood vessel. The apparatus of the invention may also be applicable toclearing occlusions from other body lumens. Specifically, the apparatusof the invention comprises a catheter having a proximal end and a distalend; a guide wire; and a guide wire attachment mechanism. In someembodiments, the apparatus may further comprise a vibration-generatingmember, said vibration-generating member operably connected to saidguide wire via said guide wire locking mechanism and an externalvibrational energy source operably attached to the vibration-generatingmember.

The guide wire attachment mechanism of the invention generatesfrictional forces on the guide wire against an attachment lumen in adefined portion of the catheter. The frictional forces are generatedwhen the portion of the guide wire containing the attachment mechanismmoves relative to the guide wire, which causes contact with the guidewire which in turn contacts the wall of the attachment lumen.Accordingly, the attachment is force-dependent. The force-dependentattachment or clamping of the guide wire to the catheter is alsoreferred to herein as partial attachment, by which is meant that theguide wire may be either freely moving within the catheter or attachedto the catheter depending on the movement of that portion of thecatheter. For example, operator may pull or push the guide wire freelywithin the catheter, while at the same time the guide wire can—at somepower limit (e.g., about 0.01-1 Newton force)—be attached to and movewith the catheter via the attachment mechanism of the invention. Theattachment mechanism may be located within a defined portion of thecatheter at some distance from the distal tip of the catheter, butpreferably is in the distal region of the catheter to improve guide wiresupport (e.g., 1-20 mm from the distal tip of the catheter), for examplein a catheter cap, as this is a more efficient arrangement.

In one embodiment, the guide wire may be attached to the catheter byfrictional forces generated when a structure in the catheter cap thatcomprises accelerator pistons accelerates relative to the guide wire.Forward acceleration of the catheter cap causes a piston to engage theguide wire by pressing it up against the attachment lumen wall therebyclamping the guide wire to the catheter. Acceleration of the cathetercap in the reverse direction causes another piston to engage the guidewire by pressing it up against the wall of the attachment lumen.

In another embodiment, the guide wire may be attached to the catheter byfrictional forces generated by movement of the guide wire in onedirection relative to the catheter. In this embodiment a spring-basedpiston presses against the guide wire, but at an angle such that theguide wire may more easily be, e.g., pushed in the distal direction (orpulled in the proximal direction) than moved in the opposite direction.

In yet another embodiment, the guide wire may be attached to thecatheter by frictional forces generated against the guide wire as itpasses through a specially designed lumen. This embodiment takesadvantage of the frictional forces that a lumen wall may exert against abent guide wire.

In still another embodiment, the guide wire may be attached to thecatheter by frictional forces generated at least in part by a highfriction surface against the guide wire as it passes through theattachment lumen of the catheter cap.

In a further embodiment, the guide wire may be attached to the catheterby frictional forces against the guide wire as it passes through thecatheter cap lumen, where the frictional forces are generated at leastin part by changes in the diameter of attachment lumen as the cathetercap is oscillated.

The aforementioned embodiments, as well as other embodiments, deliverymethods, different designs and variations of the guide wire attachmentmechanism of the invention are discussed and explained below withreference to the accompanying drawings. Note that the drawings areprovided as an exemplary understanding of the present invention and toschematically illustrate particular embodiments of the presentinvention. The skilled person will readily recognize other similarexamples equally within the scope of the invention. The drawings are notintended to limit the scope of the present invention defined in theappended claims.

One embodiment of the guide wire attachment means is depicted in FIGS.1A-1B. In this embodiment, a portion of the catheter containsacceleration pistons 110 a, 110 b that may comprise a cylinder 113 a,113 b or a ball 114 a, 114 b that is capable of moving freely through aslot 111 a, 111 b towards a guide wire attachment lumen 135 to push aguide wire towards the wall of the attachment lumen. A piston may bedesigned to move in a preferred direction—either in the forwarddirection (i.e., distally, toward the distal tip 121 of the catheter) orthe backward direction (i.e., proximally), based on the angle of thepiston. In the embodiment depicted in FIGS. 1A and 1B, the preferreddirection for acceleration piston 110 a is distally and the preferreddirection for acceleration piston 110 b is proximally, as indicated bythe arrows. The portion of the catheter containing the accelerationpistons 110 a, 110 b may be anywhere along the catheter, but preferably,it is at the distal end of the catheter (not shown) in a catheter cap125. As illustrated in FIG. 1A, the acceleration piston 110 a maycomprise a slot 111 a through which the cylinder 113 a (or ball 114 a,not shown) may slide into the attachment lumen 135 toward the guide wire130 upon forward (distal) acceleration of the catheter cap 125 (as shownby the arrow), creating a friction force that couples the guide wire 130to the catheter cap 125. During distal acceleration, the cylinder 113 b(or ball 114 b, not shown) of the acceleration piston 110 b having apreferred proximal direction response, remains in the slot 111 b awayfrom the guide wire 130. Similarly, as illustrated in FIG. 1B, theacceleration piston 110 b may comprise a slot 111 b through which theball 114 b (or cylinder 113 b, not shown) may slide into the attachmentlumen 135 toward the guide wire 130 upon backward (proximal)acceleration of the catheter cap 125 (as shown by the arrow), creating afriction force that couples the guide wire 130 to the catheter cap 125.During proximal acceleration, the ball 114 a (or cylinder 113 a, notshown) of the acceleration piston 110 a having a preferred distaldirection response remains in the slot 111 a away from the guide wire130. The embodiments illustrated in FIGS. 1A and 1B depicts twoacceleration pistons 110 a, 110 b, however the catheter cap 125 maycomprise more than two acceleration pistons for a firmer hold on theguide wire 130. Alternatively, the catheter cap may comprise oneacceleration piston that is butterfly shaped (not shown), which mayrotate up into the attachment lumen to lock the guide wire uponacceleration of the catheter cap in either direction.

In another embodiment of a guide wire attachment mechanism, which isillustrated in FIG. 2, a portion of the catheter comprises a springpiston 212 for attaching a guide wire 230 to the catheter (not shown) byfriction forces against an attachment lumen 235. Preferably this portionof the catheter is a catheter cap 225 at the distal end of the catheter,as shown in FIG. 2, but the portion may be anywhere in the catheter. Thespring piston 212 is a piston comprising a spring 217 and it provides aconstant pressure against the guide wire 230, but may press the guidewire 230 more firmly against the wall of the attachment lumen 235 whenthe guide wire 230 moves in a favored direction relative to the cathetercompared when the guide wire 230 moves in the opposite (disfavored)direction. The attachment lumen 235 may be straight, as illustrated inFIG. 2, however in alternative embodiments it may comprise a curve, asshown for example as lumen 336 in FIG. 3. Combinations of the elementsof attachment mechanisms depicted in FIGS. 1-4 and as described hereinare within the skill in the art and encompassed by the invention.

Increased pressure in the favored direction may be effected by theposition of the spring piston 212 and the shape of its contact area 215.Thus, in the embodiment depicted in FIG. 2, the spring piston 212 isdesigned to favor allowing forward (distal) movement of the guide wire230 over backward (proximal) movement relative to the catheter, becausethe spring piston 212 and its contact area 215 are angled toward thedistal tip 221 of the catheter. An embodiment favoring backward movementof the guide wire 230 relative to the catheter could be achieved byangling the spring piston 212 in the opposite direction, using the sameshaped piston contact area 215 in this embodiment. In some embodimentsit may be desirable to have a neutral effect on direction of guide wire230, in which case the spring piston 212 maybe oriented orthogonal tothe guide wire 230 and the longitudinal axis of the attachment lumen235. The spring 217 in the spring piston 212 may be any type of spring,including helical, leaf spring, membrane etc. to maintain constantpressure by the contact area 215 of the spring piston 212 against theguide wire 230. In this embodiment, the guide wire 230 is attached tothe catheter cap 225 up to the force generated by the friction againstthe wall of the attachment lumen 235. The surface between the pistoncontact area 215 and the guide wire 230 and the surface between theguide wire 230 and the attachment lumen 235 can be designed to haveeither a low friction coefficient or a high friction coefficient,depending on the needs of the procedure.

In yet another embodiment of the guide wire attachment mechanism,illustrated in FIG. 3, the friction to hold the guide wire 330 isgenerated by an attachment lumen having a curved path, referred toherein as a curved attachment lumen 336. In this embodiment, a portionof the catheter comprises a curved attachment lumen 335 for bending theguide wire to generate friction forces against the guide wire (asdiscussed above) for attaching the guide wire 330 to the catheter.Preferably this portion of the catheter is a catheter cap 325 at thedistal tip 321 of the catheter. This embodiment has two modes. In afirst mode, the catheter cap 325 is stationary and the operator may pushor pull the guide wire through 330 the catheter at will. Frictionagainst the guide wire 330 is slightly higher than in catheters having astandard straight attachment lumen. In a second mode, where the cathetercap 325 accelerates, friction is generated between the guide wire 330and the curved attachment lumen 336, causing the guide wire 330 to beattached to the catheter cap 325, and thus the catheter. Specifically,when the catheter cap 325 moves, whether by the operator or byoscillation in an active catheter (not shown), the guide wire 330 isclamped to the catheter cap 325 by the frictional forces generatedagainst the guide wire 330 by the wall of the curved attachment lumen336, and the guide wire 330 moves with the catheter cap 325.

The embodiments of the a guide wire attachment means depicted in FIGS.1-3 may be used with a standard catheter, which effects coupling of theguide wire to the catheter cap when the catheter is moved in the axialdirection. However, the embodiments are also useful in conjunction withactive catheters, where energy is inputted from the proximal end of thecatheter to generate oscillations at the distal end of the catheter. Inparticular, to overcome additional limitations of the priorart—specifically the loss of mechanical energy transfer from theproximal end to the distal end of the catheter, the apparatus of theinvention is particularly useful in conjunction with active cathetershaving vibration-generating means for generating a vibration at thedistal end of the catheter, in a particular a vibration-generating meansfor generating axial oscillation of a vibration member at the distal endof the catheter.

Thus, the guide wire attachment mechanism of the invention may be usedwith standard passive catheters, that is standard endovascular cathetersused for stiff guide wire penetration procedures. Alternatively theattachment mechanism of the invention may be used with active catheters,such as catheters having vibration-generating means at the distal end ofthe catheter for penetrating a vessel occlusion, in particular activecatheters having vibration systems designed for efficiently transferringvibration energy to the distal end of the catheter. It is noted thatwhen used with an active catheter, the guide wire penetration procedureused in conjunction with the present invention may be implementedalternately with the vibrating member and occlusion impact element ofthe active catheter, as the guide wire is usually pulled inside thecatheter during operation of such an active catheter. Alternatively, anactive catheter may be designed such that vibration generating means mayboth couple the guide wire to the catheter and vibrate the guide wire,by oscillating a section of the catheter containing the guide wireattachment mechanism. Where the guide wire acts as a hammer on theocclusion, it preferably extends from about 0.1 mm to about 5 mm beyondthe catheter cap.

The present invention is particularly useful with the active cathetercomprising a pulling member-spring element combination as described indetail in co-pending published U.S. application No. 2011/0196384(recanalization), based on U.S. provisional application No. 61/302,669,entitled “Device for Recanalization of Vessel Occlusions and Method ofUse”, filed on date even herewith. The pulling member-spring elementapparatus generates a vibration force that oscillates the vibratablemember by a pulling force rather than pushing or combinedpulling-pushing force, and is less sensitive to unpredictable geometrysuch as the sometimes tortuous curvature of blood vessels than PCIdevices that use pushing forces. In particular, the apparatus ofco-pending published U.S. application no. 2011/0196384 (recanalization)comprises a spring element, a pulling member, a vibratable member, allhoused in a catheter, and an external vibrational energy source operablyconnected to the pulling member. At the distal tip of the apparatus is avibratable member, which may be, for example, a cap—similar a cathetercap, or a cap shaped to increase mechanical impact and improvepenetration. The vibratable member oscillates in response to the pullingforce of the pulling member and the return force from the springelement. The oscillation or vibration of the vibratable member caneffect penetration of the occlusion. Specifically, the vibrationalenergy source is adapted to repeatedly pull and release the pullingmember so as to vibrate the vibratable member via the spring element.The pulling member is capable of simultaneously compressing the springelement in the proximal direction and therefore transferring energy tothe vibratable member. The spring element is capable of converting thestored energy to kinetic energy locally (upon release of the pullingmember tension), thereby moving the vibratable member in the distaldirection. The acceleration of the kinetic energy carries the expansionof the spring element to extend the distal end of the spring elementbeyond the no load (resting) position, thereby pushing the vibratablemember further distally. In a blood vessel having an occlusion, thekinetic energy is transferred from the vibratable member to impact theocclusion. The vibratable member, located at the distal tip of thecatheter, is thereby made oscillate at a frequency and amplitudesufficient to penetrate an occlusion in a body lumen. When used with thepresent invention, the catheter may be a conventional interventionalmedical catheter having a lumen to accommodate the pulling member andalso a lumen to accommodate a guide wire and the guide wire attachmentmechanism of the present invention, as well as other elements such asfor steering, motion measurement element, to infuse contrast material,or to remove occlusion debris from the drilling area.

The present invention is also particularly useful with the activecatheter comprising a hydraulic lumen as described in detail inco-pending published U.S. application no. US 2009/0292296A1, entitled“Method and Device for Recanalization of Total Occlusions”. Thehydraulic mechanism transfers hydraulic pulses to the distal end of thecatheter to expand and contract a distal element thereby oscillating avibratable member at the distal end of the catheter with minimal loss ofenergy transfer. Briefly, the vibration-generating means described in US2009/0292296A1 includes a hydraulic catheter comprising a catheter headand at least one hydraulic lumen operably connected to vibrationalenergy source to input energy pulses, preferably hydraulic pressurewaves or pulses, into the at least one hydraulic lumen of the hydrauliccatheter for generating a vibration force at the distal end of thecatheter for oscillating a vibration member. The hydraulic lumen iscapable of efficiently transferring energy to a vibratable member at itsdistal tip to oscillate that vibratable member to penetrate an occlusionin a body lumen. The hydraulic lumen is a sealed structure containing aliquid, preferably a biologically compatible liquid, and having aproximal end and a distal end. The hydraulic lumen preferably comprisesa proximal element, a distal element and a hydraulic tube connecting theproximal element to the distal element.

Still referring to US 2009/0292296A1, the vibrational energy source isexternal of the catheter, but is operably connected thereto, inparticular to the hydraulic lumen of the hydraulic catheter. Preferably,the vibrational energy source is capable of generating at least one ofhydraulic pressure wave, comprising at least one frequency and at leastone amplitude, into the hydraulic lumen preferably via the proximalelement of the hydraulic lumen. The proximal element may mediateinitiating the hydraulic pressure wave through the hydraulic tubepreferably by being mechanically compressed or shaken in the proximaldirection. The hydraulic tube transmits the hydraulic pressure wave tothe distal element. The distal element may be a vibratable member or mayeffect oscillation of a vibratable member, which vibration is driven bythe hydraulic pressure wave. The distal element may be made to vibrateor oscillate by pushing liquid into it, thereby expanding it, and thenremoving the pressure, thereby allowing it to “spring back”. The distalelement may be, for example, an active bellows, an elastic membrane or aspring that is sealingly covered in an expansible or compliant material.The catheter head, which is the distal-most region of the hydrauliccatheter, comprises the distal element. The proximal and distalelements, but not the hydraulic tube, may be made to expand andcontract. Within the catheter head, the distal element of the hydrauliclumen cooperates with the hydraulic pressure waves to generate avibration force useful for penetrating a vessel occlusion.

Further referring to US 2009/0292296A1, the catheter head comprisesthree functional components: a vibratable member, a return forcecomponent and an occlusion impact element. The vibratable memberoscillates in response to the distally directed force from the hydraulicpressure waves and the proximally-directed force of the return forcecomponent. The vibration motion of the vibratable member is transferredto the occlusion impact element, which effects penetration of theocclusion. These three functional components may comprise one or morestructures. For example: the distal element of the hydraulic lumen maybe a structure that performs all three functions; the distal element ofthe hydraulic lumen may transmit a vibration energy and return force toa separate structure that is a vibratable member and occlusion impactelement; or a structure (or combination of structures) separate from thedistal element of the hydraulic lumen may comprise all three functionalcomponents. Preferably, the three functional components are built intothe distal element of the hydraulic lumen.

The present invention is not recommended for use with the embodiment ofthe hydraulic catheter that involves vibrating the guide wire. In anyevent, it should be noted that the frictional forces used to attach theguide wire in the present invention differ markedly from the guide wireanchor of US 2009/0292296A1, in that the forces are entirely passive andinternal to the device, operating as a function of movement of the guidewire or catheter. By contrast, the guide wire anchor mechanism of US2009/0292296A1 relies on externally applied forces, such as inflationmedia pumped into inflation balloons, to stabilize the guide wire duringimplementation of the vibration force. Indeed, the two mechanisms arenot interchangeable.

For both co-pending published U.S. application no. 2011/0196384(recanalization) and US 2009/0292296A1 the vibrational energy source isexternal of the catheter, but is operably connected to thevibration-generating member. The vibrational energy source may be anyenergy source that is capable of generating at least one vibratoryenergy pulse comprising at least on frequency and at least oneamplitude. The vibrational energy source may be, for example, a motor, ashaker, a piezoelectric motor or an actuator.

The guide wire attachment mechanism may be used in conjunction with anactive catheter having a vibration-generating means, such as the pullingmember-spring element described in co-pending published U.S. applicationno. 2011/0196384 (recanalization), as illustrated in FIG. 4, or thehydraulic system described in published U.S. application no. US2009/0292296A1 which comprises, e.g., a distal bellows. Elements thatare not spring-like structures but that generate an oscillation,preferably an axial oscillation, at the distal end of the catheter arealso within the scope of this combination embodiment represented by FIG.4. Thus, for example an elastic membrane as described in US2009/0292296A1, or piezomotors as described in the art, or comparablevibration-generating means, are equally contemplated components of avibration-generating means within the meaning of the present invention.One example of such a combination is illustrated in FIG. 4, whichdemonstrates how the guide wire attachment mechanism depicted in FIG. 3may be used in conjunction with an active catheter comprising avibration-generating means. In particular, FIG. 4 depicts a schematiccross-section through a catheter cap 425 comprising the curvedattachment lumen 436 embodiment shown in FIG. 3 attached to the distalend of an exemplary spring 450 of a vibration-generating means to impartaxial vibration to the guide wire 430 via the curved attachment lumen436 in the catheter cap 425. For clarity of illustration in FIG. 4, thevibration-generating means is depicted as a spring 450, which representsa means by which the catheter cap 425 may be oscillated in an axialdirection. Other combinations of a guide wire attachment mechanism, suchas those illustrated in FIGS. 1 and 2, and an active catheter (having avibration-generating means) are within the scope of the invention, asthe principle of the oscillating catheter cap effecting movement togenerate friction is the same.

In the embodiments depicted in FIGS. 5A and 5B, a high friction surface540 within the catheter cap 525 provides friction against guide wire 530as the catheter cap 525 moves relative to the guide wire 530. In theembodiment depicted in FIG. 5A, the catheter cap 525 has a straightattachment lumen 535 that lies parallel to the longitudinal axis of thecatheter cap 525 and has a diameter slightly larger than the diameter ofthe guide wire 530. FIG. 5B illustrates a similar embodiment, differingfrom the embodiment of FIG. 5A only in that the catheter cap 525 has atilted or angled attachment lumen 537. The attachment lumen 537 of FIG.5B is set at angle relative to the longitudinal axis of the catheter cap525. The attachment lumen 535, 537 has a high friction surface 540 thatincludes a high friction flexible polymeric material. The high frictionsurface 540 may be the surface of the attachment lumen 535, 537 itselfwhere the catheter cap 525 is manufactured from a relatively highfriction material, or the high friction surface 540 may be a coating onthe attachment lumen 535, 537. Suitable materials for the high frictionsurface 540 include low durometer thermoplastic polymers, such as, forexample, a polyether block amide (e.g., PEBAX) or a polyurethane. Thecatheter cap 525 may be manufactured from metal, plastic or otherbio-compatible material.

Preferably, the catheter cap 525 is used in conjunction with an activecatheter having a vibration-generating means, such as the pullingmember-spring element described in co-pending published U.S. applicationno. 2011/0196384 (recanalization), filed on date even herewith. Thus, asshown in FIGS. 5A and 5B, the catheter cap 525 may be attached to thedistal end of a compression spring 550. The proximal end of thecompression spring 550 may be attached to the catheter 220. As shown inFIGS. 5A and 5B, the catheter cap 525 may optionally have a proximalportion 526 that extends through the compression spring 550, whichprovides axial alignment relative to the compression spring 550. Theproximal-most portion of the lumen of the catheter cap 525 may flare outto form a funnel-like shape 527 to direct the guide wire 530 when it ispushed by the operator between the guide wire lumen 531 and catheter cap525. The distal-most portion of the guide wire lumen 531 may besimilarly flared 532.

In another embodiment of the guide wire attachment mechanism, theattachment lumen 635 of the catheter cap 625 may include a flexible tube641, as illustrated in FIGS. 6A and 6B. The flexible tube 641 mayprovide a high friction surface to generate frictional forces againstthe guide wire 630 as the catheter cap 625 moves relative to the guidewire 630. The flexible tube 641 preferably is longitudinally flexibleand stretchable along its axis. By longitudinally flexible is meant thatthe flexible tube 641 may bend along the longitudinal axis. Suitablematerials for the flexible tube 641 include, for example, a polyetherblock amide such as PEBAX, having a durometer of about 25; apolyurethane, such as Pellethane 80A; or similar materials.

In the embodiment depicted in FIG. 6A, the catheter cap 625 has astraight attachment lumen 635 that lies parallel to the longitudinalaxis of the catheter cap 625 and has a diameter slightly larger than thediameter of the guide wire 630. FIG. 6B illustrates a similarembodiment, differing from the embodiment of FIG. 6A only in that thecatheter cap 625 has a tilted or angled attachment lumen 637. Theattachment lumen 637 is set at slight angle relative to the longitudinalaxis of the catheter cap 625. The tilted or angled attachment lumen inembodiments of FIGS. 5B and 6B may serve two purposes. First, the angledattachment lumen 537, 637 may contribute to the frictional forcesagainst the guide wire 530, 630, as the operator pushes the cathetermore forcefully. For example, the angle between the direction of motionand the guide wire may generate lateral friction forces on the guidewire 530, 630, causing it to vibrate with the catheter cap. Second, theangled attachment lumen 537, 637 may assist in maneuvering the guidewire; for example, the catheter may be rotated to aim the guide wire ina particular direction—when used to penetrate an occlusion.

Preferably, the catheter cap 625 of the embodiments of FIGS. 6A and 6Bis used in conjunction with an active catheter having avibration-generating means, such as the pulling member-spring elementdescribed in co-pending published U.S. application no. 2011/0196384(recanalization), filed on date even herewith. Thus, as shown in FIGS.6A and 6B, the catheter cap 625 may be attached to the distal end of acompression spring 550. The proximal end of the compression spring 550may be attached to the catheter 220. As shown in FIGS. 6A and 6B, thecatheter cap 625 may optionally have a proximal portion 626 that extendsthrough the compression spring 650, which provides axial alignmentrelative to the compression spring 650. The flexible tube 641 may beattached at its distal end 642 to the distal tip of the catheter cap625, extends through the attachment lumen 635, 637, and may be attachedat is proximal end to a portion of the catheter. As shown in theembodiments of FIGS. 6A and 6B, the flexible tube 641 may extend beyondthe proximal portion 626 of the catheter cap 625, and be attached at itsproximal end to the distal end of the guide wire lumen 631. Where theflexible tube 641 is used in an active catheter as shown in FIGS. 6A and6B, in addition to providing friction against the guide wire 630, theflexible tube 641 may change its inner diameter as the compressionspring 650, or other vibration-generating means, contracts or expands,thereby effectively changing the attachment lumen diameter and theprobability that the guide wire 630 will encounter frictional surface.

The inner diameter of the flexible tube 641 changes as the compressionspring compresses or expands. Specifically, when the compression spring650 is in a compressed state, the flexible tube 641 has a smaller innerdiameter due to wrinkling inward and increased contact with the guidewire 630, thereby increasing the friction generated against the guidewire 630. The wrinkling (or collapsing inward) of the flexible tube 641when the compression spring 650 is compressed may occur because theflexible tube 641 is bounded from the outside by the inner wall of thecatheter cap 625. Extension of the compression spring 650, expands theflexible tube 641 and also provides a smaller inner diameter, therebyincreasing the friction generated against the guide wire 630. Bycomparison, when the compression spring 650 is in a relaxed state, itprovides less friction against the guide wire 630 than when the flexibletube 641 is contracted or extended.

Thus, the apparatus of the invention may comprise the following. Anapparatus for penetrating a vessel occlusion, comprising: a catheter; aguide wire; a guide wire attachment mechanism located within a portionof said catheter; wherein said guide wire attachment mechanism iscapable of generating friction forces on said guide wire upon movementof said portion of said catheter relative to said guide wire to couplesaid guide wire to said catheter. In one embodiment, said portion ofsaid catheter is a catheter cap located at a distal end of saidcatheter. In one embodiment, said attachment mechanism comprises anattachment lumen and two or more acceleration pistons. In anotherembodiment, said attachment mechanism comprises an attachment lumen anda spring piston. In yet another embodiment said attachment mechanismcomprises a curved attachment lumen. In still another embodiment, saidattachment mechanism comprises an attachment lumen having a highfriction surface comprising a flexible polymer. In one aspect of thisembodiment the attachment lumen is set at an angle relative to thelongitudinal axis of said catheter cap. In still yet another embodiment,said attachment mechanism comprises an attachment lumen having aflexible tube, said flexible tube comprising a smaller diameter uponcontraction and a larger diameter upon extension compared to a relaxedstate. In one aspect of this embodiment the attachment lumen is set atan angle relative to the longitudinal axis of said catheter cap.

In one embodiment, the apparatus may further comprise avibration-generating member, said vibration-generating member operablyconnected to said guide wire via said guide wire attachment mechanism;and a vibrational energy source operably connected to saidvibration-generating member, wherein said vibrational energy source isadapted to generate at least one oscillation at a distal end of saidcatheter via said vibration-generating member. In one aspect of thisembodiment said vibration-generating member is selected from the groupconsisting of: a spring element and a pulling member; a hydraulic lumenand a distal bellows; a hydraulic lumen and an elastic membrane; and apiezomotor.

The apparatus may additionally comprise a steering device to assistnavigation through an occlusion, especially for use in cases where thereare numerous bifurcations near the target occlusion. The catheter may becompatible for use with additional external or internal components thatassist visualization of the apparatus or device, and/or to removedrilling debris, for example by suction.

Preferably the catheter has one or more lumens for a guide wire, and oneor more lumens for operation of the vibration-generating member. Thecatheter may also include various lumens for other features, such as asteering wire or other mechanism, contrast materials for visualization,IVUS (intra-vascular ultrasound), elements for measuring distal motionamplitude and force, removal of debris from the occlusion, etc.

The invention additionally encompasses a method of attaching a guidewire to a catheter for use in re-canalization of occluded vessel. Themethod of coupling a guide wire to a catheter for use in penetrating avessel occlusion, may comprise: providing a catheter having anattachment mechanism and a guide wire threaded therethrough; and movingsaid attachment mechanism relative to said guide wire to generatefriction forces on said guide wire sufficient to couple said guide wireto said catheter. In one embodiment, said attachment mechanism comprisesan attachment lumen and two or more acceleration pistons and said movingstep includes accelerating said attachment mechanism relative to saidguide wire. In another embodiment, said attachment mechanism comprisesan attachment lumen and a spring piston, said spring piston having ashape that favors free movement of said guide wire in a direction at aforce, and said moving step includes moving said attachment mechanism ina direction and force unfavorable to free movement of said guide wire.In yet another embodiment, said attachment mechanism comprises a curvedattachment lumen, and said moving step includes moving said attachmentmechanism so as to generate friction from a wall surface of said curvedattachment lumen against said guide wire. In one embodiment, theproviding step may further include providing a vibration generatingmeans, wherein the method further comprises: generating a vibrationforce via said vibration-generating means; said moving step includingusing said vibration force to generate at least a portion of saidfriction.

The invention additionally encompasses a method of treating a vesselocclusion. The method may comprise: introducing into a vessel having anocclusion a catheter having an attachment mechanism and a guide wirethreaded therethrough; coupling said guide wire to said catheter bymoving said attachment mechanism relative to said guide wire to generatefriction forces on said guide wire; and penetrating said occlusion usingsaid coupled guide wire. In one embodiment said catheter furtherincludes a vibration-generating means, said method further comprising:generating a vibration force via said vibration-generating means; saidcoupling step including using said vibration force to generate at leasta portion of said friction. In one aspect of this embodiment saidvibration force vibrates a vibrating member capable of penetrating saidvessel occlusion and said penetrating step includes using said vibrationforce alternately with said coupled guide wire. The method may furthercomprise: adjusting periodically the position of said guide wirerelative to said catheter so that said guide wire extends from a distaltip of said catheter by a defined amount. Said defined amount may bebetween about 1 mm-20 mm, or between about 5 mm-15 mm, or between about5 mm and 10 mm, or between 0.1 mm to about 5 mm.

It will be appreciated by persons having ordinary skill in the art thatmany variations, additions, modifications, and other applications may bemade to what has been particularly shown and described herein by way ofembodiments, without departing from the spirit or scope of theinvention. Therefore it is intended that scope of the invention, asdefined by the claims below, includes all foreseeable variations,additions, modifications or applications.

What is claimed is:
 1. A method of coupling a guide wire to a catheterfor use in penetrating a vessel occlusion, said catheter having anattachment mechanism, the method comprising: guiding said catheter andattachment mechanism over said guide wire; and moving said attachmentmechanism relative to said guide wire to generate friction forces onsaid guide wire sufficient to reversibly couple said guide wire to saidcatheter in a force-specific manner.
 2. A method of coupling a guidewire to a catheter for use in penetrating a vessel occlusion, saidcatheter comprising an attachment lumen having a guide wire attachmentmechanism, comprising: guiding said catheter over said guide wire,wherein said guide wire is threaded through said attachment lumen andattachment mechanism; and moving said attachment lumen relative to saidguide wire to generate friction forces on said guide wire sufficient toreversibly couple said guide wire to said catheter, wherein saidcoupling is longitudinally force-specific.
 3. The method according toclaim 1 or 2, wherein said attachment mechanism comprises two or moreacceleration pistons and said moving step includes accelerating saidattachment mechanism relative to said guide wire.
 4. The methodaccording to claim 1 or 2, wherein said attachment mechanism comprisessaid spring piston, and said moving step includes moving said attachmentlumen and attachment mechanism in a direction and force unfavorable tofree movement of said guide wire.
 5. The method according to claim 1 or2, wherein said attachment mechanism comprises a curve in saidattachment lumen, and said moving step includes moving said attachmentmechanism so as to generate friction from a wall surface of said curvedattachment lumen against said guide wire.
 6. The method according toclaim 1 or 2, wherein said providing step further includes providingsaid vibration generating member and said vibrational energy source, themethod further comprising: generating a vibration force via saidvibration-generating member; said moving step including using saidvibration force to generate at least a portion of said friction.
 7. Amethod of treating a vessel occlusion, comprising: introducing into avessel having an occlusion a catheter comprising an attachment lumenhaving a guide wire attachment mechanism; guiding said catheter oversaid guide wire, wherein said guide wire is threaded through saidattachment lumen and attachment mechanism; reversibly coupling saidguide wire to said catheter via said attachment mechanism; andpenetrating said occlusion using said coupled guide wire.
 8. The methodaccording to claim 7, wherein said catheter further includes saidvibration-generating member and said vibrational energy source, saidmethod further comprising: generating a vibration force via saidvibration-generating member; said coupling step including using saidvibration force to generate at least a portion of said friction.
 9. Themethod according to claim 8, wherein said vibration force vibrates avibrating member capable of penetrating said vessel occlusion and saidpenetrating step includes using said vibration force alternately withsaid coupled guide wire.